This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section.
With the current trends in integrated circuit (IC) miniaturization, and increasingly smaller critical dimensions, it is desirable in semiconductor device technology to integrate many different functions on a single chip.
The back end of line (BEOL) is the second portion of IC fabrication where the individual devices (transistors, capacitors, resistors, etc.) get interconnected with wiring on the wafer, the metallization layer. Common metals are Copper interconnect and Aluminum interconnect. BEOL generally begins when the first layer of metal is deposited on the wafer. BEOL includes contacts, insulating layers (dielectrics), metal levels, and bonding sites for chip-to-package connections.
Capacitors come in different varierties. Air capacitors are capacitors which use air as their dielectric. The simplest air capacitors are made of two conductive plates separated by an airgap. Air capacitors can be made in a variable or fixed capacitance form.
Metal-insulator-metal (MIM) capacitors, which are well suited for use in these integrated circuits, is a particular type of capacitor having two metal plates disposed around a capacitor dielectric. They are rather large in size, being several hundred micrometers wide (i.e., depending on the capacitance, which is much larger than a transistor or memory cell, for example). MIM capacitors are typically used for example as decoupling capacitors for microprocessors, radio-frequency (RF) capacitors in high frequency circuits, and filter and analog capacitors in mixed-signal products. MIM capacitors are playing an important role in implementation of new integrated circuit designs, and improvements in MIM capacitors continue.
The current invention moves beyond these techniques and materials.
Abbreviations that may be found in the specification and/or the drawing figures are defined below:
3-D three-dimensional
BEOL back end of the line
CMP chemical metal process
Cu copper
CVD chemical vapor deposition
IC integrated circuit
ILD inter-layer dielectric
K dielectric constant
MIM metal-insulator-metal
POR process of record
RF radio frequency
SiCO silicon oxycarbide
Ta tantalum
TaN tantalum nitride
Abbreviations not listed above would retain their meaning based on the context herein and the art discussed.